scholarly journals The effect of the shape of gaps on microenvironmental conditions and seedling recruitment in Molinietum caeruleae meadows

2015 ◽  
Vol 32 (2) ◽  
pp. 143-151 ◽  
Author(s):  
Kinga Kostrakiewicz-Gierałt
Keyword(s):  
Secondary Succession ◽  
Seedling Recruitment ◽  
Light Availability ◽  
Life Forms ◽  
Plant Canopy ◽  
Natural Habitats ◽  
Young Tree ◽  
Tree Communities ◽  
Negative Effect ◽  
Tussock Grasses

Cessation of the management of semi-natural habitats such as grasslands and meadows contributes to secondary succession and encroachment of native and alien tall-growing perennials, large tussock grasses, shrubs, and trees. Thus, the formation of gaps in the plant canopy and litter, enabling seedling recruitment, appears to be a very effective method for the restoration of several plant communities. The main objective of the research was to assess the effect of the shape of openings on microenvironmental conditions and seedling recruitment in <em>Molinietum caeruleae</em> patches in various habitat conditions. In all study patches, circular and linear openings, comparable in area, were randomly created through the removal of plant canopy and litter layer. The circular gaps presented greater light availability and lower soil humidity than linear openings, while soil temperature within differently shaped openings was similar. Regardless of differences in microenvironmental conditions, the total number of seedlings in differently shaped gaps did not vary considerably. Three plant categories were found: (i) those recruited mostly in circular openings, (ii) those recruited mostly in linear gaps, (iii) those colonizing circular and linear gaps similarly. The colonizers of circular gaps represented various synecological groups (ruderal, grasslands and meadows, young tree communities) and diverse life forms (therophytes, hemicryptophytes, chamaephytes, phanerophytes), while the colonizers of linear gaps were meadow and grassland hemicryptophytes. The formation of linear openings contributes to increases in the abundance of meadow taxa, while the creation of circular openings may have a negative effect, contributing to the promotion of the secondary succession process.

Enhanced light interception and light use efficiency explain overyielding in young tree communities

2021 ◽  
Author(s):  
Laura J. Williams ◽  
Ethan E. Butler ◽  
Jeannine Cavender‐Bares ◽  
Artur Stefanski ◽  
Karen E. Rice ◽  
...  
Keyword(s):  
Light Interception ◽  
Light Use Efficiency ◽  
Young Tree ◽  
Tree Communities ◽  
Use Efficiency

scholarly journals Spatiotemporal Patterns and Mechanisms of Chinese Tallowtree (Triadica sebifera) Spread along Edge Habitat in a Coastal Landscape, Mississippi, USA

2018 ◽  
Vol 11 (3) ◽  
pp. 117-126 ◽  
Author(s):  
Zhaofei Fan ◽  
Shaoyang Yang ◽  
Xia Liu
Keyword(s):  
Seed Dispersal ◽  
Negative Binomial ◽  
Seedling Recruitment ◽  
Light Availability ◽  
Spatiotemporal Patterns ◽  
Tree Age ◽  
Triadica Sebifera ◽  
Factors Affecting ◽  
Edge Habitat ◽  
Dispersal Mechanism

AbstractChinese tallowtree [Triadica sebifera(L.) Small] has reached unprecedented prevalence in coastal landscapes in the Gulf of Mexico, especially along edge habitat with low competition and abundant resource (e.g., light) availability. This study investigated the spatiotemporal patterns and mechanisms ofT. sebiferaspread along roadways and fire lines.Triadica sebiferaindividuals and landscape and community features were surveyed in equally spaced, spatially mapped plots. AllT. sebiferaindividuals were felled to determine tree age and status (seed trees or non-seed bearing trees), andT. sebiferaseed and seedling (≤2 yr old) densities and community and landscape features (over- and understory conditions, distance to seed trees) were measured. A zero-inflated negative binomial model was used to evaluate factors affectingT. sebiferaseed dispersal and seedling recruitment contributing to the observed spatiotemporal patterns. Introduced into the Grand Bay National Wildlife Refuge around 30 yr ago,T. sebiferatrees distribute in clustered patterns along roadways and fire lines and exhibit an exponential growth in density. HighT. sebiferaseed and seedling densities mainly occurred in sites that are ≤250 m from seed trees or have sparse overstory and high understory grass/herb coverage. With respect to the avian seed dispersal mechanism, the spatiotemporal patterns ofT. sebiferaspread along roadways and fire lines could be simply characterized by using landscape and community features that influence avian behaviors, including distance to seed trees, overstory tree density, and ground grass/herb coverage.

Elevational gradients of bryophyte diversity, life forms, and community assemblage in the southern Appalachian Mountains

2010 ◽  
Vol 40 (11) ◽  
pp. 2164-2174 ◽  
Author(s):  
Sarah E. Stehn ◽  
Christopher R. Webster ◽  
Janice M. Glime ◽  
Michael A. Jenkins
Keyword(s):  
Community Composition ◽  
Elevation Gradient ◽  
Light Availability ◽  
Basal Area ◽  
Life Forms ◽  
High Elevation ◽  
Canopy Openness ◽  
Fine Scale ◽  
Elevational Gradients ◽  
Community Assemblage

We investigated the influence of fine-scale elevational gradients and overstory disturbance on bryophyte distribution, diversity, and community composition. Bryophyte species cover and richness were sampled across 60 randomly selected plots within high-elevation spruce–fir ( Picea – Abies ) forests of Great Smoky Mountains National Park. Ordination and regression analyses revealed a fine-scale elevation gradient (700 m) in bryophyte community composition. Observed changes in bryophyte diversity and community composition were also associated with variation in deciduous basal area and thus litter composition, the prevalence of herbaceous plants, and the degree of canopy openness resulting from balsam woolly adelgid ( Adelges piceae Ratz.) infestation. Although overstory disturbances, such as those caused by the adelgid, create suitable substrate for bryophyte colonization, the corresponding increase in light availability and deciduous basal area may alter bryophyte diversity and community assemblages.

scholarly journals Edge effects alter the role of fungi and insects in mediating functional composition and diversity of seedling recruits in a fragmented tropical forest

2020 ◽  
Vol 126 (7) ◽  
pp. 1181-1191
Author(s):  
Meghna Krishnadas ◽  
Kavya Agarwal ◽  
Liza S Comita
Keyword(s):  
Tropical Forest ◽  
Functional Diversity ◽  
Seed Size ◽  
Wood Density ◽  
Edge Effects ◽  
Seedling Recruitment ◽  
Light Availability ◽  
Canopy Openness ◽  
Dry Matter Content ◽  
Forest Fragments

Abstract Background and Aims In fragmented forests, proximity to forest edges can favour the establishment of resource-acquisitive species over more resource-conservative species. During seedling recruitment, resource-acquisitive species may benefit from either higher light availability or weaker top-down effects of natural enemies. The relative importance of light and enemies for recruitment has seldom been examined with respect to edge effects. Methods In a human-modified wet tropical forest in India, we first examined how functional traits indicative of resource-acquisitive vs. resource-conservative strategies, i.e. specific leaf area (SLA), leaf dry matter content, wood density and seed size, explained interspecific differences in densities of seedling recruits with distance to the forest edge. Then, we checked whether fungicide and insecticide treatments and canopy openness (proxy for light availability) explained edge effects on trait-mediated changes in seedling density. Finally, we examined whether light availability and natural enemy activity explained edge effects on functional diversity of seedling recruits. Key Results Up to 60 m from edges, recruit densities increased with decreasing seed size, but not at 90–100 m, where recruit densities increased with higher SLA. Trait-mediated variation in recruit densities changed with pesticides only at 90–100 m: compared with control plots, fungicide increased recruit densities for low SLA species and insecticide increased smaller seeded species. For SLA, wood density and seed size, functional diversity of recruits was higher at 90–100 m than at 0–5 m. At 90–100 m, fungicide decreased functional diversity for SLA and insecticide reduced seed size diversity compared with control plots. Canopy openness explained neither variation in recruit density in relation to traits nor functional diversity. Conclusions Altered biotic interactions can mediate local changes to trait composition and functional diversity during seedling recruitment in forest fragments, hinting at downstream effects on the structure and function of human-modified forests.

scholarly journals Effects of invasive plant species on species diversity: implications on ruderal vegetation in Bratislava City, Slovakia, Central Europe

2019 ◽  
Vol 88 (2) ◽  
Author(s):  
Alena Rendeková ◽  
Karol Mičieta ◽  
Michal Hrabovský ◽  
Mariana Eliašová ◽  
Ján Miškovic
Keyword(s):  
Invasive Species ◽  
Species Diversity ◽  
Central Europe ◽  
Invasive Plant ◽  
Urban Ecosystem ◽  
Ruderal Vegetation ◽  
Natural Habitats ◽  
Environmental Threats ◽  
Negative Effect ◽  
Invasive Taxa

Invasive species pose one of the most serious global environmental threats. Our study aimed to examine the correlation between the proportion of invasive alien taxa and species diversity of ruderal vegetation in the urban ecosystem of Bratislava, located in Central Europe. Ruderal habitats serve as the means of spread of invasive species to seminatural and natural habitats. Twenty-six invasive taxa were recorded among the ruderal vegetation of Bratislava. The majority of the recorded invasive species were neophytes, which came from North America and represent the Asteraceae family. Half of them were introduced accidentally, whereas the remaining species were introduced deliberately. Correlation and regression analyses showed that the proportion of invasive taxa has a negative effect on the species diversity of all the analyzed syntaxa in the ruderal vegetation of Bratislava.

Effect of cutting intensity on microenvironmental conditions and regeneration dynamics in yellow birch – conifer stands

2008 ◽  
Vol 38 (2) ◽  
pp. 317-330 ◽  
Author(s):  
Marcel Prévost
Keyword(s):  
Seedling Recruitment ◽  
Block Design ◽  
Light Availability ◽  
Abies Balsamea ◽  
Basal Area ◽  
Soil Disturbance ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
Partial Cutting ◽  
Randomized Block Design

This paper presents the 5 year results of different cutting intensities (removal of 0%, 40%, 50%, 60%, and 100% of the basal area) applied in two mixed yellow birch ( Betula alleghaniensis Britt.) – conifer stands of eastern Quebec, Canada. Two sites 90 km apart were used: Armagh and Duchesnay. Each site had four replicates of the treatments in a randomized block design. The effect on light availability was similar in the two sites: the 0%, 40%, 50%, 60%, and 100% cuts transmitting a mean of 5%, 21%, 26%, 30%, and 94% of full light, respectively, during the first summer. Soil temperature increased only in the 100% cut (4−5 °C, maximum daily temperature). Soil disturbance during harvest was higher at Duchesnay than at Armagh, which clearly improved seedbed receptivity, particularly to yellow birch. After 5 years, treated areas contained 21 000 to 48 300 seedlings/ha at Duchesnay compared with 5500 – 10 500 seedlings/ha at Armagh. Significant losses of coniferous advance growth were observed at both sites, but a subsequent seedling recruitment occurred only at Duchesnay. Red spruce ( Picea rubens Sarg.) showed superior establishment in the 60% cut (4400 seedlings/ha) than under other cutting intensities (1600–2100 seedlings/ha), whereas balsam fir ( Abies balsamea (L.) Mill.) responded well to all partial cutting treatments. At both sites, pin cherry ( Prunus pensylvanica L.f.) was the main competing species in the 100% cut, whereas densities of the preestablished mountain maple ( Acer spicatum Lamb.) and striped maple ( Acer pensylvanicum L.) either remained the same or increased in the partial cuts.

Response of plant species to abandonment of subalpine fields, Manang, Nepal

2012 ◽  
Vol 8 ◽  
pp. 10-15
Author(s):  
Chitra Bahadur Baniya
Keyword(s):  
Plant Species ◽  
Secondary Succession ◽  
Detrended Correspondence Analysis ◽  
Spatial Dimension ◽  
Life Forms ◽  
Plant Science ◽  
Central Nepal ◽  
Abandoned Fields ◽  
Three Stages ◽  
Composition Pattern

Spatial dimension of abandoned fields has been expanding more in rural subalpine zones of Nepal leading to various patterns of secondary succession. The secondary succession in the subalpine Himalayas has not yet been evaluated. Here, I describe a study initiated in Manang district, Central Nepal where enough abandoned fields of different chronosequences were located. A definitive successional pattern was predicted from the data obtained from sampling 256 plots of 1 × 1 m2 each systematically in a total of 43 abandoned fields from 1 to 55 years after abandonment. Change in composition pattern of 11 most important plant species was analyzed through the Detrended Correspondence Analysis (DCA). The first two axes of DCA explained 19.1 % of the total variation in the species composition. Early, mid and late successions were three stages distinguished each by their abundance scores and life-forms composition. Malva neglecta, Phleum alpinum and Fagopyrum esculentum were dominant at the recently abandoned fields. Cynoglossum zeylanicum, Malaxis muscifera, Medicago falcata and Pennisetum flaccidum were mid succession species, and Thymus linearis, Tanacetum gossypinum, Pinus wallichiana and Poa annua represented the late succession species.doi: http://dx.doi.org/10.3126/botor.v8i0.5553 Botanica Orientalis – Journal of Plant Science (2011) 8: 10-15

Morphological optimization in the largest living foraminifera: implications from finite element analysis

Paleobiology ◽  
1994 ◽  
Vol 20 (1) ◽  
pp. 14-26 ◽  
Author(s):  
Yan Song ◽  
R. Gary Black ◽  
Jere H. Lipps
Keyword(s):  
Finite Element ◽  
Chemical Exchange ◽  
Light Availability ◽  
Volume Ratio ◽  
Element Model ◽  
Lower Surface ◽  
Three Dimension ◽  
Geologic History ◽  
Natural Habitats ◽  
Element Analysis

Benthic foraminifera have attained gigantic sizes many times throughout geologic history. To understand the selective processes underlying foraminiferal gigantism, we used a computer-based, three-dimension, solid finite element model to analyze the mechanical strength of different discoid forms, including two of the largest living foraminifera—Cycloclypeus carpenteri Brady and Marginopora vertebralis Quoy and Gaimard. These two species enlarge by cyclic, planar growth, resulting in slightly biconvex (C. carpenteri) and slightly biconcave (M. vertebralis) forms. As the tests enlarge, the maximum stresses induced by a standard bending moment decrease in both species. Such stress-reducing growth plans apparently allow growth to extraordinarily large sizes and allow volume to increase with minimal lowering of the surface-to-volume ratio, a critical functional factor in ensuring increased surface area for photosynthesis by endosymbionts contained within the tests and for chemical exchange by the foraminifera with the external environment. Of the two species, M. vertebralis has a stronger construction and a lower surface-to-volume ratio. These features indicate optimal constructional solutions to environmental constraints (degree of turbulence and light availability) in their disparate natural habitats: M. vertebralis in the mechanically rigorous inter- to subtidal, and C. carpenteri on the light-minimal and hydraulically quieter, deeper sea beds. We conclude that morphological design in larger foraminifera is constrained by a biomechanical factor, and that gigantism and biomechanical optimization are demonstrably related.

scholarly journals A study of soil seed banks across one complete chronosequence of secondary succession in a karst landscape

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10226
Author(s):  
Xiaole He ◽  
Li Yuan ◽  
Zhen Hong Wang ◽  
Zizong Zhou ◽  
Li Wan
Keyword(s):  
Species Richness ◽  
Seed Germination ◽  
Secondary Succession ◽  
Life Forms ◽  
Seed Banks ◽  
Similar Species ◽  
Seed Density ◽  
Rocky Desertification ◽  
Karst Landscape ◽  
Before And After

Anthropogenic disturbance and distinctive geochemistry have resulted in rocky desertification in many karst regions of the world. Seed banks are crucial to vegetation regeneration in degraded karst ecosystems characterized by a discontinuous distribution of soil and seasonal drought stress. However, the dynamics of seed banks across one complete series of secondary succession and the underlying mechanisms remain unclear. We selected eight typical stages during secondary succession, conducted aboveground vegetation survey and collected 960 soil samples in the Guiyang karst landscape of China. Seed density, species richness and plant life forms in seed banks were determined via the germination method. The results indicated that the seed density in seed banks before and after field seed germination was significantly different among most succession stages. Community succession had impacts on the seed density of seed banks before and after field seed germination. Seed density ranged from 1,042 seedlings.m−2 in evergreen broadleaf forests to 3,755 seedlings.m−2 in the herb community, which was a relatively high density. The seed density and similar species composition between the seed banks and vegetation declined with succession from early to later stages. Species richness in seed banks was highest in middle succession stages and increased with increasing species richness of aboveground vegetation. The species richness of the five life forms in the seed banks showed different variations across these succession stages. The conservation of diverse aboveground vegetation can maintain the diversity of seed banks for restoration.

scholarly journals Plastic Biodegradation through Insects and their Symbionts Microbes: A Review

2021 ◽  
Vol 8 (4) ◽  
pp. 95-103
Author(s):  
Huda Bilal ◽  
Hasnain Raza ◽  
Haseena Bibi ◽  
Tehmina Bibi
Keyword(s):  
Environmental Issues ◽  
Life Forms ◽  
Plastic Waste ◽  
Natural Habitats ◽  
Environmentally Sustainable ◽  
Global Environmental Problems ◽  
Lack Of Information ◽  
Global Environmental ◽  
The Face

Plastic waste has recently been identified as one of the most serious environmental issues, affecting all life forms, natural habitats, and the economy, and is one of the most serious global environmental problems, second only to climate change. Seeking alternative environmentally sustainable options, such as biodegradation instead of conventional disposal, is critical in the face of this challenge. However, there is currently a lack of information about the mechanisms and efficacy of plastic biodegradation. From this perspective, this study aims to illustrate the negative environmental impacts of the plastic waste. It also addresses the role of insects and gut microbiota in the degradation of plastics, emphasizing the important role they will play in the future.

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